diff --git a/tools/nfdc/command-definition.hpp b/tools/nfdc/command-definition.hpp
index 7d8c8f0..5661ff2 100644
--- a/tools/nfdc/command-definition.hpp
+++ b/tools/nfdc/command-definition.hpp
@@ -1,5 +1,5 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
+/*
  * Copyright (c) 2014-2017,  Regents of the University of California,
  *                           Arizona Board of Regents,
  *                           Colorado State University,
@@ -49,6 +49,12 @@
    */
   ANY,
 
+  /** \brief boolean
+   *
+   * The argument appears in CommandArguments as bool.
+   */
+  BOOLEAN,
+
   /** \brief non-negative integer
    *
    *  The argument appears in CommandArguments as uint64_t.